Found a good response to Ebert's latest at Gamasutra.
Thing is, I don't think that it matters all that much. Ebert's writings on this are notorious mostly because they're novel. Most people, if they think about it at all, wouldn't have too much trouble with the idea that games are art. The objections appear to come mostly from those who are defending other forms from being "sullied" by games. Since most people under the age of 30 don't see games as "sullying" anything, I doubt that that perspective will endure.
It's a question of time. Nothing more.